Greece remained the most dubious factor in the Balkan situation. There was no doubt where her interests lay, for the only two allies of the Central Empires were Turkey and Bulgaria, one the ancient tyrant, and the other the modern rival, of the Greeks. But Greece was divided in mind between her faith in a brilliant future and her fear of German success. Her king, with his Prussian queen and marshal's baton, was interested in the success of the German Army and of the principle of royal autocracy; and his wishes made him doubt the prospects of her foes. Apart from the Court and official influence, he was given a hold on his people by the fame which had been fathered on him in the Balkan Wars of 1912-13 and the fable that he was another Constantine the Great. So far his doubts seemed to have more justification than the faith of Venizelos; and Greece had in return for her security put up with an unconstitutional government and the shame of her broken Serbian treaty. But the strain which Constantine put upon the patience of his people reached the breaking-point in 1916. In May, acting under his orders, Greek troops admitted the Bulgars into Forts Rupel and Dragotin, the keys of the Struma Valley. Popular protests were made at Salonika, where Constantine's writ did not run; and the Entente retorted with a pacific blockade in June. But in spite of a shuffle of ministers, the Court held on its pro-German way and did whatever it could, by secret communications with Berlin and facilities for German submarines, to hamper the Entente preparations for an offensive from Salonika. Early in August Sarrail, who was now commander-in-chief, ordered a French attack on Doiran, and Doldjeli was taken. Probably this was no more than a feint, for the real design was farther west, where the Serbians under Prince Alexander were looking forward to Monastir. Their offensive was anticipated by the Bulgars, who after some pourparlers with Rumania, were induced or constrained by their German masters to attack on the 17th. In the west Florina and Banitza were seized on Greek territory, and on the east the whole of new Greece, including Seres, Kavalla, and Demirhissar, as far as the Struma; the Greek garrisons surrendered and were sent to Germany as the Kaiser's guests (see Map, p. 151).